Liquid crystal display device and manufacturing method of liquid crystal display device

Abstract

The present invention provides a manufacturing method of a liquid crystal display device capable of achieving uniform alignment of monostable ferroelectric liquid crystal having spontaneous polarization, and provides the liquid crystal display device. The liquid crystal (monostable ferroelectric liquid crystal having spontaneous polarization) showing a phase sequence, either isotropic liquid phase-cholesteric phase-chiral smectic C phase, isotropic liquid phase-chiral nematic phase-chiral smectic C phase, or isotropic liquid phase-cholesteric phase-smectic A phase-chiral smectic C phase, from a high temperature side to a low temperature side, is sandwiched between two glass substrates having transparent electrodes and alignment films whose pretilt angle is not more than 2° and rubbing directions are parallel. In an alignment treatment which is performed to obtain a monostable state after heating the liquid crystal, an electric field with electric field strength of not less than 2 V/mum is applied in the vicinity of the transition temperature from a higher temperature phase than chiral smectic C phase to the chiral smectic C phase.

Description

[0001] The present invention relates to a manufacturing method of a liquid crystal display device and the liquid crystal display device, and more particularly relates to a manufacturing method of a liquid crystal display device using a liquid crystal having spontaneous polarization, and the liquid crystal display device.DESCRIPTION OF THE RELATED ART[0002] Along with the development of information-oriented society, small electronic apparatuses and mobile electronic apparatuses have been used. Accordingly, there is a demand for a small-size, light-weight, low-power consuming display unit for such electronic apparatuses, and then liquid crystal display devices that have superior characteristics compared to other display devices are in wide use.[0003] The liquid crystal display devices are mainly classified into a transmission type and a reflection type. From the viewpoint of visibility, transmission type liquid crystal display devices using a back-light are more widely adopted, and co...

AI Technical Summary

Problems solved by technology

In order to achieve high display screen brightness, a high brightness back-light is necessary, and therefore the consumption of power increases.

Besides, since a color display is realized using color filters, a single pixel needs to be composed of three sub-pixels, and therefore a high-resolution display is difficult to be achieved and the displayed colors do not have sufficient purity.

With a monostable ferroelectric liquid crystal, in general, by only introducing the liquid crystal into an empty liquid crystal panel, it is impossible to obtain uniform alignment of the liquid crystal in the chiral smectic C phase which is used in display.

The conventional alignment treatment suffers from a problem that, despite the application of a DC voltage, uniform alignment of liquid crystal can not be obtained and a high contrast ratio can not be achieved.

It is considered that this problem is caused by other factors that dominate the alignment state of the liquid crystal.

Black and white dots are present together, countless minute defects are seen, and a uniform black state is not obtained.

In short, it can be understood that the alignment treatment was not sufficient due to the low applied voltage in the alignment treatment, and a uniform alignment state was not obtained.

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